= Sinatra
Sinatra is a DSL for quickly creating web applications in Ruby with minimal
effort:
# myapp.rb
require 'sinatra'
get '/' do
'Hello world!'
end
Install the gem and run with:
gem install sinatra
ruby -rubygems myapp.rb
View at: http://localhost:4567
It is recommended to also run gem install thin, which Sinatra will
pick up if available.
== Routes
In Sinatra, a route is an HTTP method paired with a URL-matching pattern.
Each route is associated with a block:
get '/' do
.. show something ..
end
post '/' do
.. create something ..
end
put '/' do
.. replace something ..
end
patch '/' do
.. modify something ..
end
delete '/' do
.. annihilate something ..
end
options '/' do
.. appease something ..
end
Routes are matched in the order they are defined. The first route that
matches the request is invoked.
Route patterns may include named parameters, accessible via the
params hash:
get '/hello/:name' do
# matches "GET /hello/foo" and "GET /hello/bar"
# params[:name] is 'foo' or 'bar'
"Hello #{params[:name]}!"
end
You can also access named parameters via block parameters:
get '/hello/:name' do |n|
"Hello #{n}!"
end
Route patterns may also include splat (or wildcard) parameters, accessible
via the params[:splat] array:
get '/say/*/to/*' do
# matches /say/hello/to/world
params[:splat] # => ["hello", "world"]
end
get '/download/*.*' do
# matches /download/path/to/file.xml
params[:splat] # => ["path/to/file", "xml"]
end
Route matching with Regular Expressions:
get %r{/hello/([\w]+)} do
"Hello, #{params[:captures].first}!"
end
Or with a block parameter:
get %r{/hello/([\w]+)} do |c|
"Hello, #{c}!"
end
=== Conditions
Routes may include a variety of matching conditions, such as the user agent:
get '/foo', :agent => /Songbird (\d\.\d)[\d\/]*?/ do
"You're using Songbird version #{params[:agent][0]}"
end
get '/foo' do
# Matches non-songbird browsers
end
Other available conditions are +host_name+ and +provides+:
get '/', :host_name => /^admin\./ do
"Admin Area, Access denied!"
end
get '/', :provides => 'html' do
haml :index
end
get '/', :provides => ['rss', 'atom', 'xml'] do
builder :feed
end
You can easily define your own conditions:
set(:probability) { |value| condition { rand <= value } }
get '/win_a_car', :probability => 0.1 do
"You won!"
end
get '/win_a_car' do
"Sorry, you lost."
end
=== Return Values
The return value of a route block determines at least the response body passed
on to the HTTP client, or at least the next middleware in the Rack stack.
Most commonly, this is a string, as in the above examples. But other values are
also accepted.
You can return any object that would either be a valid Rack response, Rack
body object or HTTP status code:
* An Array with three elements: [status (Fixnum), headers (Hash), response body (responds to #each)]
* An Array with two elements: [status (Fixnum), response body (responds to #each)]
* An object that responds to #each and passes nothing but strings to the given block
* A Fixnum representing the status code
That way we can, for instance, easily implement a streaming example:
class Stream
def each
100.times { |i| yield "#{i}\n" }
end
end
get('/') { Stream.new }
=== Custom Route Matchers
As shown above, Sinatra ships with built-in support for using String patterns
and regular expressions as route matches. However, it does not stop there. You
can easily define your own matchers:
class AllButPattern
Match = Struct.new(:captures)
def initialize(except)
@except = except
@captures = Match.new([])
end
def match(str)
@captures unless @except === str
end
end
def all_but(pattern)
AllButPattern.new(pattern)
end
get all_but("/index") do
# ...
end
Note that the above example might be over-engineered, as it can also be
expressed as:
get // do
pass if request.path_info == "/index"
# ...
end
Or, using negative look ahead:
get %r{^(?!/index$)} do
# ...
end
== Static Files
Static files are served from the ./public directory. You can specify
a different location by setting the :public option:
set :public, File.dirname(__FILE__) + '/static'
Note that the public directory name is not included in the URL. A file
./public/css/style.css is made available as
http://example.com/css/style.css.
== Views / Templates
Each template language is exposed as via its own rendering method. These
methods simply return a string:
get '/' do
erb :index
end
This renders views/index.erb.
Instead of a template name, you can also just pass in the template content
directly:
get '/' do
code = "<%= Time.now >"
erb code
end
Templates take a second argument, the options hash:
get '/' do
erb :index, :layout => :post
end
This will render views/index.erb embedded in the
views/post.erb (default is views/layout.erb, if it exists).
Any options not understood by Sinatra will be passed on to the template
engine:
get '/' do
haml :index, :format => :html5
end
You can also set options per template language in general:
set :haml, :format => :html5
get '/' do
haml :index
end
Options passed to the render method override options set via +set+.
Available Options:
[locals]
List of locals passed to the document. Handy with partials.
Example: erb "<%= foo %>", :locals => {:foo => "bar"}
[default_encoding]
String encoding to use if uncertain. Defaults to
settings.default_encoding.
[views]
Views folder to load templates from. Defaults to settings.views.
[layout]
Whether to use a layout (+true+ or +false+), if it's a Symbol, specifies
what template to use. Example: erb :index, :layout => !request.xhr?
[content_type]
Content-Type the template produces, default depends on template language.
[scope]
Scope to render template under. Defaults to the application instance. If you
change this, instance variables and helper methods will not be available.
[layout_engine]
Template engine to use for rendering the layout. Useful for languages that
do not support layouts otherwise. Defaults to the engine used for the
temple. Example: set :rdoc, :layout_engine => :erb
Templates are assumed to be located directly under the ./views
directory. To use a different views directory:
set :views, settings.root + '/templates'
One important thing to remember is that you always have to reference
templates with symbols, even if they're in a subdirectory (in this
case, use :'subdir/template'). You must use a symbol because
otherwise rendering methods will render any strings passed to them
directly.
=== Available Template Languages
Some languages have multiple implementations. To specify what implementation
to use (and to be thread-safe), you should simply require it first:
require 'rdiscount' # or require 'bluecloth'
get('/') { markdown :index }
=== Haml Templates
Dependency:: {haml}[http://haml-lang.com/]
File Extensions:: .haml
Example:: haml :index, :format => :html5
=== Erb Templates
Dependency:: {erubis}[http://www.kuwata-lab.com/erubis/] or
erb (included in Ruby)
File Extensions:: .erb, .rhtml or .erubis (Erubis
only)
Example:: erb :index
=== Builder Templates
Dependency:: {builder}[http://builder.rubyforge.org/]
File Extensions:: .builder
Example:: builder { |xml| xml.em "hi" }
It also takes a block for inline templates (see example).
=== Nokogiri Templates
Dependency:: {nokogiri}[http://nokogiri.org/]
File Extensions:: .nokogiri
Example:: builder { |xml| xml.em "hi" }
It also takes a block for inline templates (see example).
=== Sass Templates
Dependency:: {sass}[http://sass-lang.com/]
File Extensions:: .sass
Example:: sass :stylesheet, :style => :expanded
=== SCSS Templates
Dependency:: {sass}[http://sass-lang.com/]
File Extensions:: .scss
Example:: scss :stylesheet, :style => :expanded
=== Less Templates
Dependency:: {less}[http://www.lesscss.org/]
File Extensions:: .less
Example:: less :stylesheet
=== Liquid Templates
Dependency:: {liquid}[http://www.liquidmarkup.org/]
File Extensions:: .liquid
Example:: liquid :index, :locals => { :key => 'value' }
Since you cannot call Ruby methods (except for +yield+) from a Liquid
template, you almost always want to pass locals to it.
=== Markdown Templates
Dependency:: {rdiscount}[https://github.com/rtomayko/rdiscount],
{redcarpet}[https://github.com/tanoku/redcarpet],
{bluecloth}[http://deveiate.org/projects/BlueCloth],
{kramdown}[http://kramdown.rubyforge.org/] *or*
{maruku}[http://maruku.rubyforge.org/]
File Extensions:: .markdown, .mkd and .md
Example:: markdown :index, :layout_engine => :erb
It is not possible to call methods from markdown, nor to pass locals to it.
You therefore will usually use it in combination with another rendering
engine:
erb :overview, :locals => { :text => markdown(:introduction) }
Note that you may also call the +markdown+ method from within other templates:
%h1 Hello From Haml!
%p= markdown(:greetings)
Since you cannot call Ruby from Markdown, you cannot use layouts written in
Markdown. However, it is possible to use another rendering engine for the
template than for the layout by passing the :layout_engine option.
=== Textile Templates
Dependency:: {RedCloth}[http://redcloth.org/]
File Extensions:: .textile
Example:: textile :index, :layout_engine => :erb
It is not possible to call methods from textile, nor to pass locals to it. You
therefore will usually use it in combination with another rendering engine:
erb :overview, :locals => { :text => textile(:introduction) }
Note that you may also call the +textile+ method from within other templates:
%h1 Hello From Haml!
%p= textile(:greetings)
Since you cannot call Ruby from Textile, you cannot use layouts written in
Textile. However, it is possible to use another rendering engine for the
template than for the layout by passing the :layout_engine option.
=== RDoc Templates
Dependency:: {rdoc}[http://rdoc.rubyforge.org/]
File Extensions:: .rdoc
Example:: textile :README, :layout_engine => :erb
It is not possible to call methods from rdoc, nor to pass locals to it. You
therefore will usually use it in combination with another rendering engine:
erb :overview, :locals => { :text => rdoc(:introduction) }
Note that you may also call the +rdoc+ method from within other templates:
%h1 Hello From Haml!
%p= rdoc(:greetings)
Since you cannot call Ruby from RDoc, you cannot use layouts written in
RDoc. However, it is possible to use another rendering engine for the
template than for the layout by passing the :layout_engine option.
=== Radius Templates
Dependency:: {radius}[http://radius.rubyforge.org/]
File Extensions:: .radius
Example:: radius :index, :locals => { :key => 'value' }
Since you cannot call Ruby methods directly from a Radius template, you almost
always want to pass locals to it.
=== Markaby Templates
Dependency:: {markaby}[http://markaby.github.com/]
File Extensions:: .mab
Example:: markaby { h1 "Welcome!" }
It also takes a block for inline templates (see example).
=== Slim Templates
Dependency:: {slim}[http://slim-lang.com/]
File Extensions:: .slim
Example:: slim :index
=== Creole Templates
Dependency:: {creole}[https://github.com/minad/creole]
File Extensions:: .creole
Example:: creole :wiki, :layout_engine => :erb
It is not possible to call methods from creole, nor to pass locals to it. You
therefore will usually use it in combination with another rendering engine:
erb :overview, :locals => { :text => creole(:introduction) }
Note that you may also call the +creole+ method from within other templates:
%h1 Hello From Haml!
%p= creole(:greetings)
Since you cannot call Ruby from Creole, you cannot use layouts written in
Creole. However, it is possible to use another rendering engine for the
template than for the layout by passing the :layout_engine option.
=== CoffeeScript Templates
Dependency:: {coffee-script}[https://github.com/josh/ruby-coffee-script]
and a {way to execute javascript}[https://github.com/sstephenson/execjs/blob/master/README.md#readme]
File Extensions:: .coffee
Example:: coffee :index
=== Embedded Templates
get '/' do
haml '%div.title Hello World'
end
Renders the embedded template string.
=== Accessing Variables in Templates
Templates are evaluated within the same context as route handlers. Instance
variables set in route handlers are directly accessible by templates:
get '/:id' do
@foo = Foo.find(params[:id])
haml '%h1= @foo.name'
end
Or, specify an explicit Hash of local variables:
get '/:id' do
foo = Foo.find(params[:id])
haml '%h1= bar.name', :locals => { :bar => foo }
end
This is typically used when rendering templates as partials from within
other templates.
=== Inline Templates
Templates may be defined at the end of the source file:
require 'sinatra'
get '/' do
haml :index
end
__END__
@@ layout
%html
= yield
@@ index
%div.title Hello world!!!!!
NOTE: Inline templates defined in the source file that requires sinatra are
automatically loaded. Call enable :inline_templates explicitly if you
have inline templates in other source files.
=== Named Templates
Templates may also be defined using the top-level template method:
template :layout do
"%html\n =yield\n"
end
template :index do
'%div.title Hello World!'
end
get '/' do
haml :index
end
If a template named "layout" exists, it will be used each time a template
is rendered. You can individually disable layouts by passing :layout => false
or disable them by default via set :haml, :layout => false:
get '/' do
haml :index, :layout => !request.xhr?
end
=== Associating File Extensions
To associate a file extension with a template engine, use
Tilt.register. For instance, if you like to use the file extension
+tt+ for Textile templates, you can do the following:
Tilt.register :tt, Tilt[:textile]
=== Adding Your Own Template Engine
First, register your engine with Tilt, then create a rendering method:
Tilt.register :myat, MyAwesomeTemplateEngine
helpers do
def myat(*args) render(:myat, *args) end
end
get '/' do
myat :index
end
Renders ./views/index.myat. See https://github.com/rtomayko/tilt to
learn more about Tilt.
== Filters
Before filters are evaluated before each request within the same
context as the routes will be and can modify the request and response. Instance
variables set in filters are accessible by routes and templates:
before do
@note = 'Hi!'
request.path_info = '/foo/bar/baz'
end
get '/foo/*' do
@note #=> 'Hi!'
params[:splat] #=> 'bar/baz'
end
After filters are evaluated after each request within the same context and can
also modify the request and response. Instance variables set in before filters
and routes are accessible by after filters:
after do
puts response.status
end
Note: Unless you use the +body+ method rather than just returning a String from
the routes, the body will not yet be available in the after filter, since it is
generated later on.
Filters optionally take a pattern, causing them to be evaluated only if the
request path matches that pattern:
before '/protected/*' do
authenticate!
end
after '/create/:slug' do |slug|
session[:last_slug] = slug
end
Like routes, filters also take conditions:
before :agent => /Songbird/ do
# ...
end
after '/blog/*', :host_name => 'example.com' do
# ...
end
== Helpers
Use the top-level helpers method to define helper methods for use in
route handlers and templates:
helpers do
def bar(name)
"#{name}bar"
end
end
get '/:name' do
bar(params[:name])
end
=== Using Sessions
A session is used to keep state during requests. If activated, you have one
session hash per user session:
enable :sessions
get '/' do
"value = " << session[:value].inspect
end
get '/:value' do
session[:value] = params[:value]
end
Note that enable :sessions actually stores all data in a cookie. This
might not always be what you want (storing lots of data will increase your
traffic, for instance). You can use any Rack session middleware: in order to
do so, do *not* call enable :sessions, but instead pull in your
middleware of choice how you would any other middleware:
use Rack::Session::Pool, :expire_after => 2592000
get '/' do
"value = " << session[:value].inspect
end
get '/:value' do
session[:value] = params[:value]
end
To improve security, the session data in the cookie is signed with a session
secret. A random secret is generate for you by Sinatra. However, since this
secret will change with every start of your application, you might want to
set the secret yourself, so all your application instances share it:
set :session_secret, 'super secret'
If you want to configure it further, you may also store a hash with options in
the +sessions+ setting:
set :sessions, :domain => 'foo.com'
=== Halting
To immediately stop a request within a filter or route use:
halt
You can also specify the status when halting:
halt 410
Or the body:
halt 'this will be the body'
Or both:
halt 401, 'go away!'
With headers:
halt 402, {'Content-Type' => 'text/plain'}, 'revenge'
It is of course possible to combine a template with +halt+:
halt erb(:error)
=== Passing
A route can punt processing to the next matching route using pass:
get '/guess/:who' do
pass unless params[:who] == 'Frank'
'You got me!'
end
get '/guess/*' do
'You missed!'
end
The route block is immediately exited and control continues with the next
matching route. If no matching route is found, a 404 is returned.
=== Triggering Another Route
Sometimes +pass+ is not what you want, instead you would like to get the result
of calling another route. Simply use +call+ to achieve this:
get '/foo' do
status, headers, body = call env.merge("PATH_INFO" => '/bar')
[status, headers, body.map(&:upcase)]
end
get '/bar' do
"bar"
end
Note that in the example above, you would ease testing and increase performance
by simply moving "bar" into a helper used by both /foo
and /bar.
If you want the request to be sent to the same application instance rather than
a duplicate, use call! instead of call.
Check out the Rack specification if you want to learn more about call.
=== Setting Body, Status Code and Headers
It is possible and recommended to set the status code and response body with the
return value of the route block. However, in some scenarios you might want to
set the body at an arbitrary point in the execution flow. You can do so with the
+body+ helper method. If you do so, you can use that method from there on to
access the body:
get '/foo' do
body "bar"
end
after do
puts body
end
It is also possible to pass a block to +body+, which will be executed by the Rack
handler (this can be used to implement streaming, see "Return Values").
Similar to the body, you can also set the status code and headers:
get '/foo' do
status 418
headers \
"Allow" => "BREW, POST, GET, PROPFIND, WHEN"
"Refresh" => "Refresh: 20; http://www.ietf.org/rfc/rfc2324.txt"
body "I'm a tea pot!"
end
Like +body+, +headers+ and +status+ with no arguments can be used to access
their current values.
=== Logging
In the request scope, the +logger+ helper exposes a +Logger+ instance:
get '/' do
logger.info "loading data"
# ...
end
This logger will automatically take your Rack handler's logging settings into
account. If logging is disabled, this method will return a dummy object, so
you do not have to worry in your routes and filters about it.
Note that logging is only enabled for Sinatra::Application by
default, so if you inherit from Sinatra::Base, you probably want to
enable it yourself:
class MyApp < Sinatra::Base
configure(:production, :development) do
enable :logging
end
end
=== Mime Types
When using send_file or static files you may have mime types Sinatra
doesn't understand. Use +mime_type+ to register them by file extension:
configure do
mime_type :foo, 'text/foo'
end
You can also use it with the +content_type+ helper:
get '/' do
content_type :foo
"foo foo foo"
end
=== Generating URLs
For generating URLs you should use the +url+ helper method, for instance, in
Haml:
%a{:href => url('/foo')} foo
It takes reverse proxies and Rack routers into account, if present.
This method is also aliased to +to+ (see below for an example).
=== Browser Redirect
You can trigger a browser redirect with the +redirect+ helper method:
get '/foo' do
redirect to('/bar')
end
Any additional parameters are handled like arguments passed to +halt+:
redirect to('/bar'), 303
redirect 'http://google.com', 'wrong place, buddy'
You can also easily redirect back to the page the user came from with
redirect back:
get '/foo' do
"do something"
end
get '/bar' do
do_something
redirect back
end
To pass arguments with a redirect, either add them to the query:
redirect to('/bar?sum=42')
Or use a session:
enable :session
get '/foo' do
session[:secret] = 'foo'
redirect to('/bar')
end
get '/bar' do
session[:secret]
end
=== Cache Control
Setting your headers correctly is the foundation for proper HTTP caching.
You can easily set the Cache-Control header with like this:
get '/' do
cache_control :public
"cache it!"
end
Pro tip: Set up caching in a before filter:
before do
cache_control :public, :must_revalidate, :max_age => 60
end
If you are using the +expires+ helper to set the corresponding header,
Cache-Control will be set automatically for you:
before do
expires 500, :public, :must_revalidate
end
To properly use caches, you should consider using +etag+ and +last_modified+.
It is recommended to call those helpers *before* doing heavy lifting, as they
will immediately flush a response if the client already has the current
version in its cache:
get '/article/:id' do
@article = Article.find params[:id]
last_modified @article.updated_at
etag @article.sha1
erb :article
end
It is also possible to use a
{weak ETag}[http://en.wikipedia.org/wiki/HTTP_ETag#Strong_and_weak_validation]:
etag @article.sha1, :weak
These helpers will not do any caching for you, but rather feed the necessary
information to your cache. If you are looking for a quick caching solutions, try
{rack-cache}[http://rtomayko.github.com/rack-cache/]:
require "rack/cache"
require "sinatra"
use Rack::Cache
get '/' do
cache_control :public, :max_age => 36000
sleep 5
"hello"
end
=== Sending Files
For sending files, you can use the send_file helper method:
get '/' do
send_file 'foo.png'
end
It also takes a couple of options:
send_file 'foo.png', :type => :jpg
The options are:
[filename]
file name, in response, defaults to the real file name.
[last_modified]
value for Last-Modified header, defaults to the file's mtime.
[type]
content type to use, guessed from the file extension if missing.
[disposition]
used for Content-Disposition, possible values: +nil+ (default),
:attachment and :inline
[length]
Content-Length header, defaults to file size.
If supported by the Rack handler, other means than streaming from the Ruby
process will be used. If you use this helper method, Sinatra will automatically
handle range requests.
=== Accessing the Request Object
The incoming request object can be accessed from request level (filter, routes,
error handlers) through the request method:
# app running on http://example.com/example
get '/foo' do
t = %w[text/css text/html application/javascript]
request.accept # ['text/html', '*/*']
request.accept? 'text/xml' # true
request.preferred_type(t) # 'text/html'
request.body # request body sent by the client (see below)
request.scheme # "http"
request.script_name # "/example"
request.path_info # "/foo"
request.port # 80
request.request_method # "GET"
request.query_string # ""
request.content_length # length of request.body
request.media_type # media type of request.body
request.host # "example.com"
request.get? # true (similar methods for other verbs)
request.form_data? # false
request["SOME_HEADER"] # value of SOME_HEADER header
request.referrer # the referrer of the client or '/'
request.user_agent # user agent (used by :agent condition)
request.cookies # hash of browser cookies
request.xhr? # is this an ajax request?
request.url # "http://example.com/example/foo"
request.path # "/example/foo"
request.ip # client IP address
request.secure? # false (would be true over ssl)
request.forwarded? # true (if running behind a reverse proxy)
request.env # raw env hash handed in by Rack
end
Some options, like script_name or path_info, can also be
written:
before { request.path_info = "/" }
get "/" do
"all requests end up here"
end
The request.body is an IO or StringIO object:
post "/api" do
request.body.rewind # in case someone already read it
data = JSON.parse request.body.read
"Hello #{data['name']}!"
end
=== Attachments
You can use the +attachment+ helper to tell the browser the response should be
stored on disk rather than displayed in the browser:
get '/' do
attachment
"store it!"
end
You can also pass it a file name:
get '/' do
attachment "info.txt"
"store it!"
end
=== Looking Up Template Files
The find_template helper is used to find template files for rendering:
find_template settings.views, 'foo', Tilt[:haml] do |file|
puts "could be #{file}"
end
This is not really useful. But it is useful that you can actually override this
method to hook in your own lookup mechanism. For instance, if you want to be
able to use more than one view directory:
set :views, ['views', 'templates']
helpers do
def find_template(views, name, engine, &block)
Array(views).each { |v| super(v, name, engine, &block) }
end
end
Another example would be using different directories for different engines:
set :views, :sass => 'views/sass', :haml => 'templates', :default => 'views'
helpers do
def find_template(views, name, engine, &block)
_, folder = views.detect { |k,v| engine == Tilt[k] }
folder ||= views[:default]
super(folder, name, engine, &block)
end
end
You can also easily wrap this up in an extension and share with others!
Note that find_template does not check if the file really exists but
rather calls the given block for all possible paths. This is not a performance
issue, since +render+ will use +break+ as soon as a file is found. Also,
template locations (and content) will be cached if you are not running in
development mode. You should keep that in mind if you write a really crazy
method.
== Configuration
Run once, at startup, in any environment:
configure do
# setting one option
set :option, 'value'
# setting multiple options
set :a => 1, :b => 2
# same as `set :option, true`
enable :option
# same as `set :option, false`
disable :option
# you can also have dynamic settings with blocks
set(:css_dir) { File.join(views, 'css') }
end
Run only when the environment (RACK_ENV environment variable) is set to
:production:
configure :production do
...
end
Run when the environment is set to either :production or
:test:
configure :production, :test do
...
end
You can access those options via settings:
configure do
set :foo, 'bar'
end
get '/' do
settings.foo? # => true
settings.foo # => 'bar'
...
end
=== Available Settings
[absolute_redirects] If disabled, Sinatra will allow relative redirects,
however, Sinatra will no longer conform with RFC 2616
(HTTP 1.1), which only allows absolute redirects.
Enable if your app is running behind a reverse proxy that
has not been set up properly. Note that the +url+ helper
will still produce absolute URLs, unless you pass in
+false+ as second parameter.
Disabled per default.
[add_charsets] mime types the content_type helper will
automatically add the charset info to.
You should add to it rather than overriding this option:
settings.add_charsets << "application/foobar"
[app_file] main application file, used to detect project root,
views and public folder and inline templates.
[bind] IP address to bind to (default: 0.0.0.0).
Only used for built-in server.
[default_encoding] encoding to assume if unknown
(defaults to "utf-8").
[dump_errors] display errors in the log.
[environment] current environment, defaults to ENV['RACK_ENV'],
or "development" if not available.
[logging] use the logger.
[lock] Places a lock around every request, only running
processing on request per Ruby process concurrently.
Enabled if your app is not thread-safe.
Disabled per default.
[method_override] use _method magic to allow put/delete forms in
browsers that don't support it.
[port] Port to listen on. Only used for built-in server.
[prefixed_redirects] Whether or not to insert request.script_name into
redirects if no absolute path is given. That way
redirect '/foo' would behave like
redirect to('/foo'). Disabled per default.
[public] folder public files are served from
[reload_templates] whether or not to reload templates between requests.
Enabled in development mode.
[root] project root folder.
[raise_errors] raise exceptions (will stop application).
[run] if enabled, Sinatra will handle starting the web server,
do not enable if using rackup or other means.
[running] is the built-in server running now?
do not change this setting!
[server] server or list of servers to use for built-in server.
defaults to ['thin', 'mongrel', 'webrick'], order indicates
priority.
[sessions] enable cookie based sessions.
[show_exceptions] show a stack trace in the browser.
[static] Whether Sinatra should handle serving static files.
Disable when using a Server able to do this on its own.
Disabling will boost performance.
Enabled per default in classic style, disabled for
modular apps.
[views] views folder.
== Error Handling
Error handlers run within the same context as routes and before filters, which
means you get all the goodies it has to offer, like haml,
erb, halt, etc.
=== Not Found
When a Sinatra::NotFound exception is raised, or the response's status
code is 404, the not_found handler is invoked:
not_found do
'This is nowhere to be found.'
end
=== Error
The +error+ handler is invoked any time an exception is raised from a route
block or a filter. The exception object can be obtained from the
sinatra.error Rack variable:
error do
'Sorry there was a nasty error - ' + env['sinatra.error'].name
end
Custom errors:
error MyCustomError do
'So what happened was...' + env['sinatra.error'].message
end
Then, if this happens:
get '/' do
raise MyCustomError, 'something bad'
end
You get this:
So what happened was... something bad
Alternatively, you can install an error handler for a status code:
error 403 do
'Access forbidden'
end
get '/secret' do
403
end
Or a range:
error 400..510 do
'Boom'
end
Sinatra installs special not_found and error handlers when
running under the development environment.
== Rack Middleware
Sinatra rides on Rack[http://rack.rubyforge.org/], a minimal standard
interface for Ruby web frameworks. One of Rack's most interesting capabilities
for application developers is support for "middleware" -- components that sit
between the server and your application monitoring and/or manipulating the
HTTP request/response to provide various types of common functionality.
Sinatra makes building Rack middleware pipelines a cinch via a top-level
+use+ method:
require 'sinatra'
require 'my_custom_middleware'
use Rack::Lint
use MyCustomMiddleware
get '/hello' do
'Hello World'
end
The semantics of +use+ are identical to those defined for the
Rack::Builder[http://rack.rubyforge.org/doc/classes/Rack/Builder.html] DSL
(most frequently used from rackup files). For example, the +use+ method
accepts multiple/variable args as well as blocks:
use Rack::Auth::Basic do |username, password|
username == 'admin' && password == 'secret'
end
Rack is distributed with a variety of standard middleware for logging,
debugging, URL routing, authentication, and session handling. Sinatra uses
many of these components automatically based on configuration so you
typically don't have to +use+ them explicitly.
You can find useful middleware in
{rack}[https://github.com/rack/rack/tree/master/lib/rack],
{rack-contrib}[https://github.com/rack/rack-contrib#readme],
with {CodeRack}[http://coderack.org/] or in the
{Rack wiki}[https://github.com/rack/rack/wiki/List-of-Middleware].
== Testing
Sinatra tests can be written using any Rack-based testing library
or framework. {Rack::Test}[http://rdoc.info/github/brynary/rack-test/master/frames] is
recommended:
require 'my_sinatra_app'
require 'test/unit'
require 'rack/test'
class MyAppTest < Test::Unit::TestCase
include Rack::Test::Methods
def app
Sinatra::Application
end
def test_my_default
get '/'
assert_equal 'Hello World!', last_response.body
end
def test_with_params
get '/meet', :name => 'Frank'
assert_equal 'Hello Frank!', last_response.body
end
def test_with_rack_env
get '/', {}, 'HTTP_USER_AGENT' => 'Songbird'
assert_equal "You're using Songbird!", last_response.body
end
end
== Sinatra::Base - Middleware, Libraries, and Modular Apps
Defining your app at the top-level works well for micro-apps but has
considerable drawbacks when building reusable components such as Rack
middleware, Rails metal, simple libraries with a server component, or
even Sinatra extensions. The top-level DSL pollutes the Object namespace
and assumes a micro-app style configuration (e.g., a single application
file, ./public and ./views directories, logging, exception
detail page, etc.). That's where Sinatra::Base comes into play:
require 'sinatra/base'
class MyApp < Sinatra::Base
set :sessions, true
set :foo, 'bar'
get '/' do
'Hello world!'
end
end
The methods available to Sinatra::Base subclasses are exactly as those
available via the top-level DSL. Most top-level apps can be converted to
Sinatra::Base components with two modifications:
* Your file should require sinatra/base instead of +sinatra+;
otherwise, all of Sinatra's DSL methods are imported into the main
namespace.
* Put your app's routes, error handlers, filters, and options in a subclass
of Sinatra::Base.
Sinatra::Base is a blank slate. Most options are disabled by default,
including the built-in server. See {Options and Configuration}[http://sinatra.github.com/configuration.html]
for details on available options and their behavior.
=== Modular vs. Classic Style
Contrary to common belief, there is nothing wrong with classic style. If it
suits your application, you do not have to switch to a modular application.
There are only two downsides compared with modular style:
* You may only have one Sinatra application per Ruby process. If you plan to
use more, switch to modular style.
* Classic style pollutes Object with delegator methods. If you plan to ship
your application in a library/gem, switch to modular style.
There is no reason you cannot mix modular and classic style.
If switching from one style to the other, you should be aware of slightly
different default settings:
Setting Classic Modular
app_file file loading sinatra file subclassing Sinatra::Base
run $0 == app_file false
logging true false
method_override true false
inline_templates true false
static true false
=== Serving a Modular Application
There are two common options for starting a modular app, actively starting with
run!:
# my_app.rb
require 'sinatra/base'
class MyApp < Sinatra::Base
# ... app code here ...
# start the server if ruby file executed directly
run! if app_file == $0
end
Start with:
ruby my_app.rb
Or with a config.ru, which allows using any Rack handler:
# config.ru
require 'my_app'
run MyApp
Run:
rackup -p 4567
=== Using a Classic Style Application with a config.ru
Write your app file:
# app.rb
require 'sinatra'
get '/' do
'Hello world!'
end
And a corresponding config.ru:
require 'app'
run Sinatra::Application
=== When to use a config.ru?
Good signs you probably want to use a config.ru:
* You want to deploy with a different Rack handler (Passenger, Unicorn,
Heroku, ...).
* You want to use more than one subclass of Sinatra::Base.
* You want to use Sinatra only for middleware, but not as endpoint.
There is no need to switch to a config.ru only because you
switched to modular style, and you don't have to use modular style for running
with a config.ru.
=== Using Sinatra as Middleware
Not only is Sinatra able to use other Rack middleware, any Sinatra application
can in turn be added in front of any Rack endpoint as middleware itself. This
endpoint could be another Sinatra application, or any other Rack-based
application (Rails/Ramaze/Camping/...):
require 'sinatra/base'
class LoginScreen < Sinatra::Base
enable :sessions
get('/login') { haml :login }
post('/login') do
if params[:name] == 'admin' && params[:password] == 'admin'
session['user_name'] = params[:name]
else
redirect '/login'
end
end
end
class MyApp < Sinatra::Base
# middleware will run before filters
use LoginScreen
before do
unless session['user_name']
halt "Access denied, please login."
end
end
get('/') { "Hello #{session['user_name']}." }
end
=== Dynamic Application Creation
Sometimes you want to create new applications at runtime without having to
assign them to a constant, you can do this with Sinatra.new:
require 'sinatra/base'
my_app = Sinatra.new { get('/') { "hi" } }
my_app.run!
It takes the application to inherit from as optional argument:
require 'sinatra/base'
controller = Sinatra.new do
enable :logging
helpers MyHelpers
end
map('/a') do
run Sinatra.new(controller) { get('/') { 'a' } }
end
map('/b') do
run Sinatra.new(controller) { get('/') { 'b' } }
end
This is especially useful for testing Sinatra extensions or using Sinatra in
your own library.
This also makes using Sinatra as middleware extremely easy:
require 'sinatra/base'
use Sinatra do
get('/') { ... }
end
run RailsProject::Application
== Scopes and Binding
The scope you are currently in determines what methods and variables are
available.
=== Application/Class Scope
Every Sinatra application corresponds to a subclass of Sinatra::Base. If you
are using the top-level DSL (require 'sinatra'), then this class is
Sinatra::Application, otherwise it is the subclass you created explicitly. At
class level you have methods like +get+ or +before+, but you cannot access the
+request+ object or the +session+, as there only is a single application class
for all requests.
Options created via +set+ are methods at class level:
class MyApp < Sinatra::Base
# Hey, I'm in the application scope!
set :foo, 42
foo # => 42
get '/foo' do
# Hey, I'm no longer in the application scope!
end
end
You have the application scope binding inside:
* Your application class body
* Methods defined by extensions
* The block passed to +helpers+
* Procs/blocks used as value for +set+
* The block passed to Sinatra.new
You can reach the scope object (the class) like this:
* Via the object passed to configure blocks (configure { |c| ... })
* +settings+ from within request scope
=== Request/Instance Scope
For every incoming request, a new instance of your application class is
created and all handler blocks run in that scope. From within this scope you
can access the +request+ and +session+ object or call rendering methods like
+erb+ or +haml+. You can access the application scope from within the request
scope via the +settings+ helper:
class MyApp < Sinatra::Base
# Hey, I'm in the application scope!
get '/define_route/:name' do
# Request scope for '/define_route/:name'
@value = 42
settings.get("/#{params[:name]}") do
# Request scope for "/#{params[:name]}"
@value # => nil (not the same request)
end
"Route defined!"
end
end
You have the request scope binding inside:
* get/head/post/put/delete/options blocks
* before/after filters
* helper methods
* templates/views
=== Delegation Scope
The delegation scope just forwards methods to the class scope. However, it
does not behave 100% like the class scope, as you do not have the class
binding. Only methods explicitly marked for delegation are available and you
do not share variables/state with the class scope (read: you have a different
+self+). You can explicitly add method delegations by calling
Sinatra::Delegator.delegate :method_name.
You have the delegate scope binding inside:
* The top level binding, if you did require "sinatra"
* An object extended with the Sinatra::Delegator mixin
Have a look at the code for yourself: here's the
{Sinatra::Delegator mixin}[http://github.com/sinatra/sinatra/blob/ceac46f0bc129a6e994a06100aa854f606fe5992/lib/sinatra/base.rb#L1128]
being {included into the main namespace}[http://github.com/sinatra/sinatra/blob/ceac46f0bc129a6e994a06100aa854f606fe5992/lib/sinatra/main.rb#L28].
== Command Line
Sinatra applications can be run directly:
ruby myapp.rb [-h] [-x] [-e ENVIRONMENT] [-p PORT] [-o HOST] [-s HANDLER]
Options are:
-h # help
-p # set the port (default is 4567)
-o # set the host (default is 0.0.0.0)
-e # set the environment (default is development)
-s # specify rack server/handler (default is thin)
-x # turn on the mutex lock (default is off)
== Requirement
The following Ruby versions are officially supported:
[ Ruby 1.8.7 ]
1.8.7 is fully supported, however, if nothing is keeping you from it, we
recommend upgrading to 1.9.2 or switching to JRuby or Rubinius.
[ Ruby 1.9.2 ]
1.9.2 is supported and recommended. Note that Radius and Markaby are
currently not 1.9 compatible. Do not use 1.9.2p0, it is known to cause
segmentation faults when running Sinatra.
[ Rubinius ]
Rubinius is officially supported (Rubinius >= 1.2.3), everything, including
all template languages, works.
[ JRuby ]
JRuby is officially supported (JRuby >= 1.6.0). No issues with third party
template libraries are known, however, if you choose to use JRuby, please
look into JRuby rack handlers, as the Thin web server is not fully supported
on JRuby. JRuby's support for C extensions is still experimental, which only
affects RDiscount at the moment.
Ruby 1.8.6 is no longer supported.
We also keep an eye on upcoming Ruby versions.
The following Ruby implementations are not officially supported but still are
known to run Sinatra:
* Older versions of JRuby and Rubinius
* MacRuby, Maglev, IronRuby
* Ruby 1.9.0 and 1.9.1
Not being officially supported means if things only break there and not on a
supported platform, we assume it's not our issue but theirs.
We also run our CI against ruby-head (the upcoming 1.9.3), but we can't
guarantee anything, since it is constantly moving. Expect 1.9.3p0 to be
supported.
Sinatra should work on any operating system supported by the chosen Ruby
implementation.
== The Bleeding Edge
If you would like to use Sinatra's latest bleeding code, feel free to run your
application against the master branch, it should be rather stable.
We also push out prerelease gems from time to time, so you can do a
gem install sinatra --pre
To get some of the latest features.
=== With Bundler
If you want to run your application with the latest Sinatra, using
{Bundler}[http://gembundler.com/] is the recommended way.
First, install bundler, if you haven't:
gem install bundler
Then, in your project directory, create a +Gemfile+:
source :rubygems
gem 'sinatra', :git => "git://github.com/sinatra/sinatra.git"
# other dependencies
gem 'haml' # for instance, if you use haml
gem 'activerecord', '~> 3.0' # maybe you also need ActiveRecord 3.x
Note that you will have to list all your applications dependencies in there.
Sinatra's direct dependencies (Rack and Tilt) will, however, be automatically
fetched and added by Bundler.
Now you can run your app like this:
bundle exec ruby myapp.rb
=== Roll Your Own
Create a local clone and run your app with the sinatra/lib directory
on the $LOAD_PATH:
cd myapp
git clone git://github.com/sinatra/sinatra.git
ruby -Isinatra/lib myapp.rb
To update the Sinatra sources in the future:
cd myapp/sinatra
git pull
=== Install Globally
You can build the gem on your own:
git clone git://github.com/sinatra/sinatra.git
cd sinatra
rake sinatra.gemspec
rake install
If you install gems as root, the last step should be
sudo rake install
== Versioning
Sinatra follows {Semantic Versioning}[http://semver.org/], both SemVer and
SemVerTag.
== Further Reading
* {Project Website}[http://www.sinatrarb.com/] - Additional documentation,
news, and links to other resources.
* {Contributing}[http://www.sinatrarb.com/contributing] - Find a bug? Need
help? Have a patch?
* {Issue tracker}[http://github.com/sinatra/sinatra/issues]
* {Twitter}[http://twitter.com/sinatra]
* {Mailing List}[http://groups.google.com/group/sinatrarb/topics]
* {IRC: #sinatra}[irc://chat.freenode.net/#sinatra] on http://freenode.net
* {Sinatra Book}[http://sinatra-book.gittr.com] Cookbook Tutorial
* {Sinatra Book Contrib}[http://sinatra-book-contrib.com/] Community contributed recipes
* API documentation for the {latest release}[http://rubydoc.info/gems/sinatra]
or the {current HEAD}[http://rubydoc.info/github/sinatra/sinatra] on
http://rubydoc.info/